Gout occurs when there is too much uric acid in the body. Having high levels of uric acid in the blood is also called hyperuricemia. A combination of factors, including alcohol consumption, gender, genetics, hormonal changes, eating a purine-rich diet, and certain medications, may cause the body to produce too much or excrete too little uric acid.
The excessive uric acid forms sharp crystals (called urate) inside the joints. Urate causes the joints to become swollen, painful, and red.
Uric acid is a waste product that forms when the body breaks down purines, which are substances naturally found in the body and in certain foods (especially anchovies, mushrooms, asparagus, and organ meats, such as liver and kidneys). In healthy individuals, uric acid dissolves in the bloodstream, is filtered through the kidneys, and is excreted in the urine.
If gout is suspected, a healthcare provider will take a sample of synovial fluid from the affected joint. This sample is analyzed to look for uric acid crystals in the white blood cells. If crystals are present, a positive diagnosis is made.
If gout is diagnosed, a healthcare provider may also take a urine sample to determine how much uric acid is being excreted. This is because some cases of gout occur when individuals do not excrete enough uric acid. The patient is asked to collect his/her urine over a 24-hour period. The sample is then analyzed in a laboratory to determine if the person has higher-than-normal uric acid levels in the urine.
A uric acid blood test may also be performed to determine if the patient has high levels of uric acid in the blood.
signs and symptoms
Symptoms of gout almost always occur suddenly, especially at night. Gout causes the joints to become red, swollen, and stiff. The big toe is most commonly affected because gout symptoms typically develop in areas of the body that experience the most trauma. When the toe is affected, the symptom is often called podagra. Other commonly affected joints include the ankles, heels, knees, wrists, hands, fingers, and elbows. The pain may be so severe that a bed sheet touching the affected skin is unbearable. Symptoms generally subside after one to two weeks. Once symptoms are gone, the affected joints are not painful. However, if the patient does not receive treatment, attacks will come back (with increased frequency), and they will usually last longer and affect more joints.
Chronic arthritis and tophi: Some patients with gout develop long-term arthritis. After several years, these patients may also develop tophi, which are discolored deposits of uric acid crystals in the joints. Tophi causes areas of swelling to develop in the joints, particularly the toes, fingers, hands, elbows, earlobes, and ankles. Tophi are usually not painful, but they can help doctors diagnose the condition. Tophi may be painful if they develop inside the fluid-filled sacs (called bursae) that cushion the joints.
Joint damage: Long-term arthritis may eventually lead to permanent joint damage.
Kidney disease and kidney stones: Long-term gout may lead to decreased kidney function and possibly kidney stones. This can happen if the tubes inside the kidneys become blocked with uric acid crystals. In very severe cases, the condition may lead to kidney failure.
Consumption of alcohol, especially beer, increases the risk for gout.
Gender: Gender may also play a role because men are more likely to develop the condition than women.
Genetics: Children of parents with gout have a 20% chance of developing the condition. This suggests that genetics may be involved.
Hormonal changes: Uric acid levels increase at puberty in men and at menopause in women. This means men are more likely to develop gout when they are 30-50 years old, while women are more likely to develop the condition when they are 50-70 years old. Gout is extremely uncommon in pre-menopausal women.
Purine-rich diet: There are many factors that may cause excessive uric acid to build up in the body. Eating a purine-rich diet that includes large amounts of red meat, organ meat, and oily fish (such as salmon, sardines, and herring), may lead to the development of gout. This is because uric acid forms when purines are broken down in the body.
Some medications: Some medications, including certain diuretics, niacin (a B-complex vitamin), aspirin (taken in low doses), cyclosporine (e.g. Neoral® or Sandimmune®), and some anti-cancer drugs, may cause gout.